Pneumatic reading system for document cards

ABSTRACT

A document card reading system comprising a pneumatic switch assembly located opposite an air plenum and between which perforated document cards are passed. The plenum and switch assembly have aligned air discharge and reception ports between which jetted air flows when not blocked by a document card, and each of the reception ports is connected with a circular portion of a flexible film carrying a helical copper cladding contact portion. A contact board is disposed above the helical contact portions, and the board has cooperating contact portions of copper cladding each of which is provided with a series of slots so that the helical contact portions may in effect make edge to edge contact with the contact portions on the contact board. The helical contact portions and the contact portions on the board are sealed with respect to atmosphere by means of diaphragms of flexible film carried by a back plate located above the contact board, with small openings being provided through the contact board to provide communication between the flexible film carrying the helical contact portions and the diaphragms. A pump, such as a positive displacement pump, provides air under pressure to the plenum. Longitudinal grooves are provided in the facing surfaces of the switch assembly and plenum in communication respectively with the ports therein to prevent crosstalk or unwarranted application of pressure to any of the ports in the switch assembly not in alignment with an aperture in the document card.

United States Patent [191 Jensen et al.

[ PNEUMATIC READING SYSTEM FOR DOCUMENT CARDS [75] Inventors: Donald F. Jensen, Endicott, N.Y.; Richard E. Lagergren, Rochester, Minn.; Robert C. Lentz, Rochester, Minn.; John. R. Reidenbach, Rochester, Minn.; Robert R. Schaffer, Endicott, NY.

[73] Assignee: International Business Machines Corporation, Armonk, NY.

[22] Filed: June 25, 1971 [21] Appl. No.: 156,728

Baroin 200/83 N Primary Examiner-Maynard R. Wilbur Assistant ExaminerRobert F. Gnuse Attorney-Keith T. Bleuer et al.

[ Jan. 1, 1974 [57] ABSTRACT A document card reading system comprising a pneumatic switch assembly located opposite an air plenum and between which perforated document cards are passed. The plenum and switch assembly have aligned air discharge and reception ports between which jetted air flows when not blocked by a document card, and each of the reception ports is connected with a circular portion of a flexible film carrying a helical copper cladding contact portion. A contact board is disposed above the helical contact portions, and the board has cooperating contact portions of copper cladding each of which is provided with a series of slots so that the helical contact portions may in effect make edge to edge contact with the contact portions on the contact board. The helical contact portions and the contact portions on the board are sealed with respect to atmosphere by means of diaphragms of flexible film carried by a back plate located above the contact board, with small openings being provided through the contact board to provide communication between the flexible film carrying the helical contact portions and the diaphragms. A pump, such as a positive displacement pump, provides air under pressure to the plenum. Longitudinal grooves are provided in the facing surfaces of the switch assembly and plenum in communication respectively with the ports therein to prevent crosstalk or unwarranted application of pressure to any of the ports in the switch assembly not in alignment with an aperture in the document card.

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BACKGROUND OF THE INVENTION The invention relates to a reading system for apertured document cards and more particularly to such a system which includes a pneumatic read head or switch assembly having a plurality of switches adapted to be closed under application of air pressure transmitted through apertures in the document card.

DESCRIPTION OF THE PRIOR ART SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved document card reading system and switch assembly of the general type disclosed in said Colglazier and Snesrud patent and which is of such construction that the electrical contacts are sealed with respect to atmosphere, with the arrangement being such that portions of a flexible film carrying electrical contacts nevertheless may move without restraint under the application of air under pressure.

It is another object of the invention to provide improved contacts in such a switch assembly particularly to provide effective edge to edge contact for assuring the completion of corresponding electrical circuits.

It is still another object of the invention to provide appropriate grooves in such a switch assembly allowing venting of pressure air transmitted through the apertures of a document card to assure that crosstalk or unwarranted completion of electricalv circuits in the switch assembly does not occur.

Ina preferred form, the reading system comprises anair pump providing air to a plenum havinga row of air discharge ports therein. A switch assembly is disposed above the plenum and hasa corresponding row of air reception ports aligned with the ports-in the plenum and the spacing between the plenum and switch assembly is such that an apertured document card may be passed therebetween. The switch assembly includes a copper clad flexible film having spaced circular areas on the film in respective communication with the air reception ports in the switch assembly, and each of the areas carries a helical contact portion formed from the cladding. A contact board is disposed above the film and has a copper cladding providing a contact portion located opposite each of the helical contacts. The contact portions on the contact board are slotted so as to provide effective edge to edge electrical contact with the helical contact portions when air under pressure is applied to the corresponding areas of the flexible film. The switch assembly has a back plate carrying diaphragms of flexible film, and suitable openings are provided in the contact board allowing communication between the areas of the flexible film carrying the helical contact portions and the diaphragms so that the contact carrying areas of the flexible film are not restrained in their movement and so that the helical contact portions and the associated contact portions of the contact board are effectively sealed with respect to atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a document card reading system incorporating principles of the invention and which includes an air plenum and a pneumatic switch assembly positioned above the air plenum;

FIG. 2 is a plan view of the air plenum showing a document card about to proceed between the switch assembly and air plenum;

FIG. 3 is a sectional view on an enlarged scale taken on line 3-3 of FIG. 2;

FIG. 4 is an exploded view of the switch assembly, showing the switch assembly to include, in order, a receiver board, a first bonding film, a diaphragm board, a second bonding film, a contact board, a third bonding film, and a back plate;

FIG. 5 is a top view of the receiver board;

FIG. 6 is a fragmentary sectional view of the receiver board taken on line 6-6 of FIG. 5;

FIG. 7 is a top view of the first bonding film;

FIG. 8 is a top view of the diaphragm board;

FIG. 9 is a side view of the diaphragm board showing the layers of the diaphragm board in exploded relationship with respect to each other;

FIGS. 10 and 11 are respectively top views of first and second sublayers of the diaphragm board;

FIG. 12 is a top view of the second bonding film;

FIG. 13 is a bottom view of the contact board;

FIG. 14 is a view on an enlarged scale showing a circular contact portion of the contact board;

FIG. 15 is a bottom view of the third bonding film in the assembly; I

FIG. 16 is a bottom view of the back plate; and

FIG. 17 is a sectional view taken on line 17-17 of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENT The illustrated document card reading system comprises, in general, a plenum 10, a pump 12- for providing air under pressure to the plenum, and a pneumatic read head or switch assembly 14 positioned above the plenum 10. A series of document cards 16 each having punched openings 18 therethrough in a plurality of columns 20, which extend transversely to the direction A in which the cards move, may be passed between the plenum l0 and the read head 14; and the read head 14 provides electrical output signals which correspond to the particular ones of the openings 18 that exist in one of the columns 20.

The plenum 10 comprises a casing 22 which is closed on its bottom by means of 'a plate 24 so as to form a plenum chamber 26 within the plenum 10. The plate 24 is ported, and a conduit 28 connects the outlet of the pump 12 with the plenum chamber 26.

The pump 12 is illustrated as being of the positive dis placement type and comprises an outer casing 30 having an internal cylindrical cavity 32 therein. A rotor 34 is eccentrically disposed within the cavity 32, and the rotor carries a plurality of. radially slidable vanes 36 which are maintained in contact with the surface of the cavity 32, such as by centrifugal force. The casing 30 has an input port 38 and also has an output port 40, the port 40 being connected with the conduit 28.

The upper surface 42 of the plenum 10 is substantially flat and is provided with a series of ports 44 extending into the chamber 26. The ports 44 are arranged in a row which is at a right angle to the direction A of movement of the card 16, and the spacing of the ports 44 is the same as that of the holes 18 in the card 16, assuming that in any particular column 20, all of the holes 18 exist that may exist. The ports 44 increase in diameter from their outlets adjacent the surface 42 to their inlets as shown in FIG. 3. A groove 46 is provided in the upper surface 42 for each of the ports 44. The grooves 46 extend in the direction A for the complete length of the plenum 10.

The read head or switch assembly 14 is spaced from the plenum 10 by means of spacers 48 and 50. The read head 14 comprises a receiver board 52, a bonding film 54, a diaphragm board 56, a bonding film 58, a contact board 60, a bonding film 62, and a backplate 64 (see FIG. 4).

The receiver board 52 (see FIG. constitutes a plate having a row of openings 66a 66x disposed therethrough. The openings 66a 66x are spaced the same distances as are the openings 44 in the plenum 10, with each of the openings 66a 66x being directly disposed above one of the openings 44. The lower surface 67 of the receiver board 52 is flat except for a series of grooves 68 therein (see FIG. 6) which are of substantially the same dimensions as the grooves 46 in the plenum 10. There is a groove 68 in communication with each of the openings 66a 66x, and these grooves are in alignment and run parallel with and directly over the grooves 46 in the plenum 10. The receiver board 52 is provided with another opening 70 therethrough which is spaced from the row of openings 66a 66x in the direction A in which a document card 16 travels between the read head 14 and the plenum 10.

Grooves 72a 722: are cut into the upper surface of the receiver board 52, and these grooves are connected respectively with the openings 66a 66x. Alternate ones of the grooves 72 beginning with the groove 72b extend generally in the direction A from the corresponding opening 66 and the other grooves beginning with the groove 72a extend generally in the opposite direction. Half of the'grooves 72 are relatively short, such as the grooves 72d and 72h; and the other half of the grooves 72, such as the grooves 72b and 72f are relatively long. As will be observed from FIG. 5, half of the grooves 72 extend at a slight angle of about with respect to the direction A in one direction, and the other half of the grooves 72 extend at a corresponding angle of 10 in the oppositedirection with respect to the direction A. For example, the grooves 72b, 72d, 72s, and 72a extend in the same direction slantwise with respect to the direction A; while the grooves 72e, 72g, 72p, and 72r extend slantwise oppositely with respect to the direction A. The opening 70 is connected with a groove 74, as shown, which does not correspond to the other grooves just mentioned. v

The film 54 (see FIG. 7) is a sheet of flexible tape having adhesive on both sides for bonding purposes and has openings 76a 76x therethrough. The openings 76a 76): are respectively inthe same locations as the ends of the grooves 72a 72 x and are in communication with these grooves. It will be noted that the openings 76a 76x are disposed in four rows 78a, 78b, 78c,

and 78d; and the openings 66a 66x are disposed on a centerline 78e disposed midway between the rows 78b and 78c. An opening 80 on the row 78d is at the end of groove 74 and is in communication therewith.

The diaphragm board 56 lies in contact with the film 54. The diaphragm board 56 (see FIGS. 8 1 1) is made up of an epoxy board 82, a bonding film 84 of electrically nonconducting material, and a copper-clad flexible film 86. The board 82 (see FIG. 10) is provided with an arrangement of small diameter holes 88a 88x which are in register with the holes 76a 76x of the film 54. The film 84 is provided with an arrangement of relatively large diameter holes a 90x (see FIG. 1 1) which are respectively concentrically disposed with respect to the holes 88a 88x. The diaphragm 86 has.

the copper cladding 86a etched out in the form of round openings 92a 92x (see FIG. 8) which are concentrically disposed with respect to the openings 90a 90x. The etching is such that it leaves a helical piece 94 of the copper cladding remaining which terminates at the center in a button portion 94a in each of the openings 92; and, except for the helical portions 94, the film 86 is revealed so that the portion of the film86 within each of the openings 92 constitutes a flexible diaphragm. The copper cladding 86a is preferably gold plated.

The diaphragm board 56 has openings 88z, 90z, and 92z therein which are similar to the other openings 88, 90, and 92 and are provided for the groove 74 and opening 80 in the receiver board 52 and film 54 respectively.

The bonding film 58 (see FIG. 12) has relatively large diameter openings 96a 96.x and 962 which are respectively concentric with the openings 76a 761; and 80 in the film 54 and thereby with the other openings which are described above concentrically located with respect to the openings 76 and 80. i

The contact board 60 may be of epoxy glass (which is thus electrically non-conducting and is rigid); and, on the lower side, it has a copper cladding 98 bonded to it (see FIG. 13). The cladding 98 has areas 100a 100x lying respectively in alignment with the openings 96a 96x and each of these areas is etched out to the board 60 itself along straight parallel lines 10221, 102b, 1020, 102d, and l02e. The copper cladding 98 is also etched alonglines extending both in thedirection A and also at right angles thereto so that the copper cladding provides terminals 104a 104x and l04z on the two side edges of the contact board 60.

The contact board 60 is provided with a plurality of A relatively small diameter holes 106a 106x and 1062, which extend through the board including the copper cladding 98. These holes 106 lie withinthe respective areas 100a 100x and 1001 for purposes to be described. Y

The film 62 includes two elongate openings 108 and 110 therethrough (see FIG. 15). The opening 108 is in communication with the holes 106 disposed above a centerline 62a which is in alignment with the centerline 78e, and the opening 110 is in communication with the holes 106 that are disposed below the centerline 62a.

The backplate 64 is of substantial thickness and is formed with a pair of grooves 112 and 114 (see FIG.

flimsy film forming diaphragms are bonded onto the shoulders 122 forming the bottoms of the grooves 112 and 114. Small air bleed openings 124 extend through the backplate 64 and are in communication with the grooves 116 and 118.

The parts 52 64 are bonded together in order to make them into the diaphragm switch assembly 14 with the parts 52 64 being in contact. The films 54, 58, 62, and 84 effectively bond together the parts with which they are in contact. With the parts being so bonded together, the electrical switches, including the helical cladding contact portions 94 and the contact portions of the cladding defined by the lines 102a 102e and within the areas 100, are effectively within a container which is closed with respect to atmospheric air. These contact portions are in communication with the openings 108 and 110 and the grooves 112, 114, 116, and 118 by means of the holes 106, and the film pieces 120 effectively seal the contact portions from atmosphere.

In operation, the rotor 34 of the pump 12 is driven so that the pump provides air under pressure within the plenum chamber 26. Air discharges through the ports 44; and, assuming that there are openings 18 in register with particular ports 44, air under pressure enters the respective openings 66a 66x in receiver board 52; and air under pressure is transmitted through the connected grooves 72a 72x and the respective openings 76a 76x, 88a 88x, and 90a 90x to the respective circular portions 92a 92x of the film 86. These portions of the film 86 flex under the air pressure, and the respective helical copper-gold switch portions 94a 94x are moved into contact with the portions of the cladding'98 between and on the edges of the grooves 102a 102e of the respective cladding portions 100a 100x. Electricity is thus suppliedto the'corresponding terminals 104a 104x from cladding 86a indicating that holes 18 exist in the particular locations in the document card 16 corresponding to these terminals. With respect to the portions of the document card which in the particular column in line with the row of holes 66a 66x do not have openings 18 in them; the card 16 acts as a barrier, preventing the transfer of a pressure pulse to the receiving ports 66a 66x; and the corresponding switches including the spiral portions 94 and the corresponding parts of the cladding 98 are not made or do not make contact. I

The principal purpose of the longitudinal grooves 68 is to eliminate crosstalk between the receiver openings 66a 66x so that only an opening 18 in the card 16 in exact alignment with a port 66 will cause the corresponding switch to be closed. The ribs between the grooves 68 effectively function to isolate each of the grooves 68 and their receiver ports 66a 66x with respect to each other for this purpose.

The grooves 68 on the receiver board 52 have still another purpose. If a document card 16 were flat against the lower surface 67 of the receiver board 52 the card would prevent the air in a port 66a 66x, previously supplied with air under pressure through a document card hole 18, from immediately exhausting after the card hole has moved beyond the port 660 66x in the receiver board 52. The longitudinal grooves 68 in the lower surface of the receiver board 52 allow the immediate exhausting from a port 66a 66:: even though the card 16 may lie tightly against the lower surface 67 of the board 52, thus preventing a signal from existing too long as the card 16 passes from a position in which a particular column 20 of holes 18 is read to the position for reading the next column 20.

The longitudinal grooves 68 also have another function, namely of maintaining the document card 16 out of contact with the ports 66a 661:, thus preventing a possible blocking of these ports by lint from the card. Cards 16 in passing across the ports would tend to scrape their fibers into the ports, providing such a contamination; but, the grooves 68 hold a card 16 out of contact with the lower ends of the ports 66a 66x.

The longitudinal grooves 46 provide an air bleed for each of the ports 44 in the plenum 10 which is particularly desirable in connection with the positive displacement type of pump 12 that is illustrated. With a positive displacement pump, it is desirable to keep a constant output flow, as by means of the grooves 46 in connection with the ports 44, so that the output pressure of the pump 12 does not change materially. Without the grooves 46, such a material variation of output pressure. of the pump 12 would occur if a card '16 were tight against the upper surface 42 of the plenum 10, which could very well happen with a bent card 16. Such a bent card in this case would block all of the openings 44 so that the output of the pump 12 would effectively be reduced to zero.

In addition, the grooves 46 in the plenum 10 as well as the grooves 68 in the. diaphragm switch assembly contribute to prevent crosstalk, since the grooves on both the air receive and supply sides on the two surfaces of the card 16 are vented and both a hole and a no hole condition in the card 16 are thus vented.

It will be noted that the ports 44 in the plenum 10 are located in the card transport on a line perpendicular to the direction A of card motion, and these ports are of a converging design so as to obtain a nearly uniform air velocity across the jet at the exit from a port 44. The ports 66 in the diaphragm switch assembly are located directly across from the ports 44 so that the static air pressure head is supplied through a hole 18 in a document card to the corresponding hole 660 66x of the diaphragm switch assembly thus definitely electrically contact with the corresponding spiral cladding portion 94. The slots 102a 102e provide an edge contact with the spiral cladding portion, resulting in lower contact resistance.

It will be noted that the channels, including the grooves 72a 72x, connecting the ports with the corresponding parts of the film 86 carrying the spiral cladding portions 94 are made as small as practical; so as to keep the volume of air in them as small as practically possible to thereby improve response time for the switches.

Advantageously, the film 86 and the diaphragms 120 effectively provide closed containers for each of the switches which includes a helical cladding portion 94 and a cladding portion a 100x. The cladding porflow between the diaphragm portions of the film 86 in the openings 92 and the. diaphragm 120 when the switches are electrically made.

It is to be understood that the invention is not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited, as it .will be understood to those skilled in the art that changes may be made without departing from the principles of the invention. In particular, although the fixed displacement pump 12 has been illustrated in connection with the pneumatic read head 14, it will be understood that any source of air pressure other than the fixed displacement pump 12 may be utilized instead, such other sources of air pressure including a blower, a piston compressor, a diaphragm pump, a turbine pump, etc.

What is claimed is:

1. A diaphragm switch assembly comprising:

a substantially rigid insulating support element carrying a first contact,

a flexible electrically insulating diaphragm supported in spaced relation to said support element,

a second contact carried by said diaphragm and aligned with said first contact, and means for selectively varying the fluid pressure on one side of said diaphragm to selectively engage and disengage said second contact with said first contact, said first contact constituting a cladding on said rigid insulating support element which is divided into a plurality of segments by a plurality of substantially parallel extending slots in said cladding, said rigid support carrying a plurality of additional contacts similar to said first contact and said diaphragm carrying a plurality of additional contacts similar to said second contact each of which is adapted to engage with one of the contacts on said rigid support element,

means for isolating the pairs of contacts on said support element and said diaphragm, and

means for selectively varying the fluid pressure on one side of said diaphragm in the vicinity of said other contacts on said diaphragm so as to engage and disengage these contacts with respect to the respective contacts on said rigid support element, each of the other of said contacts on said rigid support element also being divided into a plurality of segments by a series of substantially parallel slots.

2. Pneumatic reading mechamism for apertured document cards comprising:

a plenum and a switch assembly which have facing surfaces located adjacent to each other between which a document card may pass, said plenum having a row of ports therein terminating on its said surface and said switch assembly having a corresponding row of ports each of which is in alignment with one of said ports in said plenum and terminating on said surface of said switch assembly, and

means for supplying air under pressure into said plenum so that air may be jetted through its said ports and into the ports in said switch assembly, said switch assembly including a pneumatically operated switch connected with each of said ports in the switch assembly, one of said surfaces being provided with parallel grooves formed therein each in communication with one of the ports terminating on this surface,

the pneumatic reading mechanism including means for directing the movement of the document card between said surfaces in a certain direction, both of said surfaces being provided with parallel grooves therein as aforesaid which are in communication with the said ports in said surfaces, the grooves in one of said surfaces being respectively in alignment with the grooves on the other of said surfaces.

3. A diaphragm switch assembly comprising:

a substantially rigid insulating support element carrying a first contact,

a flexible electrically insulating diaphragm supported in spaced relation to said support element,

a second contact carried by said diaphragm and aligned with said first contact, and

means for selectively varying the fluid pressure on one side of said diaphragm to selectively engage and disengage said second contact with said first contact,

means for sealing said contacts with respect to atmosphere, said sealing means including a backing plate in sealing relationship with said rigid support element and carrying a resilient film seal in communication with the two sides of said backing plate, said rigid support element having an air bleed opening therethrough adjacent said first contact for providing communication between said contacts and said film seal, said rigid support element also carrying a plurality of other contacts similar to said first contact and said flexible diaphragm also carrying additional contacts similar to said second contact each adapted to engage one of the contacts carried by said rigid support element,

means for isolating the pairs of contacts carried by said rigid support element and said diaphragm with respect to each other, and

means for selectively varying the fluid pressure on said diaphragm for selectively engaging and disengaging the others of said contacts on said diaphragm with respect to the respective contacts carried by said rigid support element, said rigid support element also being provided with a bleed opening therethrough in connection with each of the others of said contacts carried by the rigid support element and which are'in communication with said resilient film seal whereby all of said contacts are sealed with respect to atmosphere.

4. Pneumatic reading mechanism for apertured document cards comprising:

a plenum and a switch assembly which have respectively a pair of facing surfaces located adjacent each other between which a document card may pass, said plenum having a row of a plurality of closely spaced ports therein terminating on its said surface and said switch assembly having a corresponding row of ports each of which is in alignment with one of said ports in said plenum and terminating on said surface of said switch assembly, and

means for supplying air under pressure into said plenum so that air may be jetted through its said ports and into the ports in' said switch assembly, said switch assembly including a pneumatically operated switch connected with each of said ports in the switch assembly, one of said surfaces being provided with parallel grooves formed therein each in communication with one of the ports terminating on this surface, the pneumatic reading mechanism one side of said diaphragm to selectively engage including means for directing said card to move beand disengage said second contact with said first tween said surfaces in a certain direction, said contact, and grooves extending in the same direction as the dimeans for sealing said contacts with respect to atmorection of movement of the document card. 5 sphere and including a resilient film seal having one 5. Pneumatic reading mechanism as set forth in claim side in communication with atmosphere and having 4, said grooves being provided in said surface of said the other side in communication with said contacts, switch assembly. said means for sealing said contacts including a back- 6. A diaphragm switch assembly comprising: ing plate in sealing relationship with said rigid supa substantially rigid insulating support element carry- 0 port element and carrying said resilient film seal, ing a first contact, said film seal being in communication with the two a flexible electrically insulating diaphragm supported sides of said backing plate, said rigid support elein spaced relation to said support element, ment having an air bleed opening therethrough ada second contact carried by said diaphragm and jacent said first contact for providing communicaaligned with said first contact, tion between said film seal and said contacts. means for selectively varying the fluid pressure on 

1. A diaphragm switch assembly comprising: a substantially rigid insulating support element carrying a first contact, a flexible electrically insulating diaphragm supported in spaced relation to said support element, a second contact carried by said diaphragm and aligned with said first contact, and means for selectively varying the fluid pressure on one side of said diaphragm to selectively engage and disengage said second contact with said first contact, said first contact constituting a cladding on said rigid insulating support element which is divided into a plurality of segments by a plurality of substantially parallel extending slots in said cladding, said rigid support carrying a plurality of additional contacts similar to said first contact and said diaphragm carrying a plurality of additional contacts similar to said second contact each of which is adapted to engage with one of the contacts on said rigid support element, means for isolating the pairs of contacts on said support element and said diaphragm, and means for selectively varying the fluid pressure on one side of said diaphragm in the vicinity of said other contacts on said diaphragm so as to engage and disengage these contacts with respect to the respective contacts on said rigid support element, each of the other of said contacts on said rigid support element also being divided into a plurality of segments by a series of substantially parallel slots.
 2. Pneumatic reading mechanism for apertured document cards comprising: a plenum and a switch assembly which have facing surfaces located adjacent to each other between which a document card may pass, said plenum having a row of ports therein terminating on its said surface and said switch assembly having a corresponding row of ports each of which is in alignment with one of said ports in said plenum and terminating on said surface of said switch assembly, and means for supplying air under pressure into said plenum so that air may be jetted through its said ports and into the ports in said switch assembly, said switch assembly including a pneumatically operated switch connected with each of said ports in the switch assembly, one of said surfaces being provided with parallel grooves formed therein each in communication with one of the ports terminating on this surface, the pneumatic reading mechanism including means for directing the movement of the document card between said surfaces in a certain direction, both of said surfaces being provided with parallel grooves therein as aforesaid which are in communication with the said ports in said surfaces, the grooves in one of said surfaces being respectively in alignment with the grooves on the other of said surfaces.
 3. A diaphragm switch assembly comprising: a substantially rigid insulating support element carrying a first contact, a flexible electrically insulating diaphragm supported in spaced relation to said support element, a second contact carried by said diaphragm and aligned with said first contact, and means for selectively varying the fluid pressure on one side of said diaphragm to selectively engage and disengage said second contact with said first contact, means for sealing said contacts with respect to atmosphere, said sealing means including a backing plate in sealing relationship with said rigid support element and carrying a resiLient film seal in communication with the two sides of said backing plate, said rigid support element having an air bleed opening therethrough adjacent said first contact for providing communication between said contacts and said film seal, said rigid support element also carrying a plurality of other contacts similar to said first contact and said flexible diaphragm also carrying additional contacts similar to said second contact each adapted to engage one of the contacts carried by said rigid support element, means for isolating the pairs of contacts carried by said rigid support element and said diaphragm with respect to each other, and means for selectively varying the fluid pressure on said diaphragm for selectively engaging and disengaging the others of said contacts on said diaphragm with respect to the respective contacts carried by said rigid support element, said rigid support element also being provided with a bleed opening therethrough in connection with each of the others of said contacts carried by the rigid support element and which are in communication with said resilient film seal whereby all of said contacts are sealed with respect to atmosphere.
 4. Pneumatic reading mechanism for apertured document cards comprising: a plenum and a switch assembly which have respectively a pair of facing surfaces located adjacent each other between which a document card may pass, said plenum having a row of a plurality of closely spaced ports therein terminating on its said surface and said switch assembly having a corresponding row of ports each of which is in alignment with one of said ports in said plenum and terminating on said surface of said switch assembly, and means for supplying air under pressure into said plenum so that air may be jetted through its said ports and into the ports in said switch assembly, said switch assembly including a pneumatically operated switch connected with each of said ports in the switch assembly, one of said surfaces being provided with parallel grooves formed therein each in communication with one of the ports terminating on this surface, the pneumatic reading mechanism including means for directing said card to move between said surfaces in a certain direction, said grooves extending in the same direction as the direction of movement of the document card.
 5. Pneumatic reading mechanism as set forth in claim 4, said grooves being provided in said surface of said switch assembly.
 6. A diaphragm switch assembly comprising: a substantially rigid insulating support element carrying a first contact, a flexible electrically insulating diaphragm supported in spaced relation to said support element, a second contact carried by said diaphragm and aligned with said first contact, means for selectively varying the fluid pressure on one side of said diaphragm to selectively engage and disengage said second contact with said first contact, and means for sealing said contacts with respect to atmosphere and including a resilient film seal having one side in communication with atmosphere and having the other side in communication with said contacts, said means for sealing said contacts including a backing plate in sealing relationship with said rigid support element and carrying said resilient film seal, said film seal being in communication with the two sides of said backing plate, said rigid support element having an air bleed opening therethrough adjacent said first contact for providing communication between said film seal and said contacts. 